1. Field of the Invention
The present invention relates to a chip feeder and a chip supplying system and particularly to the art of preventing chips from being damaged.
2. Related Art Statement
A chip feeder is used for, e.g., supplying electric components ("ECs") in the form of chips, to an electric-component ("EC") mounting system. A chip feeder known as a "bulk" feeder stores a number of "leadless" ECs that have no lead wires, in a loose state, i.e., in bulk in a case thereof, and supplies the ECs, one by one, from an EC-supply portion thereof. There is known an EC supplying system which includes (a) a plurality of bulk feeders which are provided on a table such that respective EC-supply portions of the bulk feeders are arranged along a line (e.g., a straight line, or a curved line such as an arc); and (b) a table moving device which moves the table in a direction parallel to the above line, to position sequentially the respective EC-supply portions of the bulk feeders at a predetermined EC-supply position.
However, the above-indicated EC supplying system has a problem that when the table starts, or stops, moving, the EC chips move, in the case, like a wave because of inertia and may be damaged. The EC chips present in a lower portion of the mass of EC chips stored in bulk in the case are engaged with one another and accordingly can hardly move. On the other hand, the EC chips present in an upper portion of the mass of EC chips can easily move so that the EC chips may collide with one another or the walls of the case, or may be subjected to friction with one another. Thus, the EC chips may be damaged. For example, the surfaces of electrodes of an EC chip may be blackened, which lowers the wettability of the electrodes that is important when the EC chip is soldered to a circuit substrate such as a printed circuit board. Thus, the soldering of the EC ship to the circuit substrate may fail.
In the above-indicated background, it has been practiced that one or more partition plates are provided in the case to part an inner space of the case into a plurality of narrow rooms with respect to a direction parallel to the direction of movement of the table. With the partition plates, the movement of the EC chips in the case can be limited, without having to decreasing the overall width of the inner space of the case (i.e., the dimension of the inner space in the direction parallel to the direction of movement of the table). In the case, the EC chips are stored in the narrow room defined by, and between, each pair of adjacent partition plates, or one partition plate and its adjacent wall surface of the case, so that the movement of the EC chips is effectively limited. Thus, even if the EC chips may move because of inertia, the maximum velocity or kinetic energy of the EC chips can be decreased, so that the EC chips may be prevented from being damaged because of collision with one another or the walls of the case.
However, there are some cases where the damaging of EC chips cannot be effectively prevented even though one or more partition plates may be provided in the case. With the partition plates, the inner space of the case is parted into a plurality of rooms. However, if the case has only a single outlet through which the EC chips are discharged, the case needs a communication passage which communicates the plurality of rooms with each other and which permits all the EC chips to be moved to one of the rooms that communicates with the outlet and be discharged through the outlet. To this end, each of the partition plates is formed with an opening which communicates the two rooms on both sides of the each plate, with each other. However, the opening of each partition plate cannot limit the movement of the EC chips, so that when the table moves, the EC chips may collide, with a great kinetic energy, with one another or the walls of the case, or may be subjected to friction with one another. This may lead to damaging so heavily the EC chips, e.g., blackening the electrodes of the EC chips, that the soldering of the EC chips may fail.
While the foregoing explanation relates to EC chips, chips other than ECs may be damaged for the same reason as described above.